NAME

isdn.conf − configuration file for ISDN/X.25 interface

DESCRIPTION

The isdn.conf file contains the software configuration parameters for the ISDN/X.25 interface.  It is used by isdnload(8) when downloading the interface. Changes to isdn.conf require re-run of isdnload(8) to take effect.

The electrical characteristics, including the configuration as an ISDN or X.25 interface, are selected by jumpers on the board. 

Each line in isdn.conf contains one parameter identifier and the associated value.  A “#” indicates the beginning of a comment; characters up to the end of the line are ignored.  The configurable parameters are described in the following. 

d_protcolSignalling protocol (D-channel) employed by your ISDN.  Must be the first parameter in isdn.conf, and should be one of the following. 

q.931following CCITT 1988 Recommendations.
nttfor INSnet64 of NTT, and for ISDN of
KDD, Japan.

addressSpecifies the X.121 DTE address (for X.25), or the E.164 or Multiple Subscriber Number address (for ISDN).  Multiple Subscriber Number (MSN, sometimes called Direct Dial-In) is a supplementary service to discriminate between terminals on the passive bus; only calls with a destination address matching the configured value are accepted.  The MSN address usually consists of the last digit(s) of the subscriber number.  If MSN is not used, this parameter may be omitted. 

sub_addrOptional E.164 subaddress (for ISDN only).  Only incoming calls with a matching subaddress are accepted.  Omit this parameter if your ISDN does not support subaddressing.  Currently a subaddress may consist of up to 19 IA5 (alias ascii(7)) characters, but the use of non-decimal digits may cause problems in interworking with non-ISDN networks. Depending on the development of the communication standards, future releases of this software may only accept decimal digits in subaddresses.

subaddr_format
Selects the presentation of ISDN subaddresses as ia5 (International Alphabet No.5, almost like ascii(7)) or bcd (preferred binary encoding, presenting the IA5 value −32 as two BCD digits).  The latter is explicitly called for by CCITT Rec. X.213, but nevertheless most terminal equipment today uses ia5 representation.  Default value is ia5 (except for the March 1990 release of NWB-236 software which follows X.213). 

max_lcnHighest Logical Channel Number (for PSPDN, or for ISDN B-channel packet switch).  All channels from 1 to max_lcn are two-way and used for virtual calls; Permanent Virtual Circuits (PVCs) are currently not supported. 

max_pkt_size
Default maximum packet size (for PSPDN, or for ISDN B-channel packet switch). Must be a power of 2. Default value is 256.

window_size
Specifies X.25 packet layer default window size (for PSPDN, or for ISDN B-channel packet switch). Default value is 7.

d_max_lcn
Highest Logical Channel Number (for ISDN D-channel packet switch). All channels from 1 to d_max_lcn are two-way and used for virtual calls; Permanent Virtual Circuits (PVCs) are currently not supported. 

d_max_pkt_size
Default maximum packet size (for ISDN D-channel packet switch). Must be 128 or 256. Default value is 256.

d_window_size
Specifies X.25 packet layer default window size (for ISDN D-channel packet switch). Default value is 7.

packet_channel
Specifies which channel is preferred when you subscribe both B-channel and D-channel packet switch.

prefer_b   use B-channel preferably(default)
prefer_d   use D-channel preferably

x25_plpSelects whether you use X.25 Packet Layer Protocol or not.  Only when you use dl(4), specify off. 

lapb_addrSelects X.25 data link address.  When running LAPB end-to-end via a leased line, one end should use dte (data terminal equipment, address A=3), otherwise use dce (data circuit-terminating equipment, address B=1).  Default is dte. 

automodeSpecify on to allow IP to establish ISDN/X.25 connections on demand.  To be used in conjunction with isdnd(8). Default is off. 

broadcastSpecify on to allow IP to send broadcast packets (generated locally) via an established ISDN/X.25 connection.  Use this option with care, since it may prevent isdnd(8) from deestablishing the connection. Default is off. 

compressSpecify on to allow IP to send packets with compressed headers (see RFC1144) via ISDN/X.25.  Default is off. 

EXAMPLES

The first example can be used for an ISDN access to NTT’s INSnet64, Japan.  For backward compatibility with the March 1990 release it uses bcd representation of subaddresses. 

d_protocolntt
address5123-4567
sub_addr4711
subaddr_formatbcd
automodeon

The last example shows an X.25 configuration file for NTT’s DDX−P.  The line is subscribed with four logical channels.  The DTE address is specified omitting the 4-digit Data Network Identification Code (DNIC, 4401 for DDX-P). 

address2345671
max_lcn4
window_size3
automodeon

SEE ALSO

isdnload(8), isdnset(8), RFC1144

BUGS

Automode may fail to establish a connection due to call collision or network congestion.  Timeouts and retry counters in applications should take this into account. 

Wrong configuration parameters are likely to cause functional problems and may invalidate PTT approvals (if any). 

NEWS-OSRelease 4.1C